Multiplying lens

Abstract

The invention discloses a magnification lens. Comprising a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with negative focal power, a sixth lens with positive focal power and a seventh lens with positive focal power which are sequentially arranged from an object space to an image space along an optical axis, an eighth negative lens with negative focal power, a ninth negative lens with negative focal power, a tenth lens with negative focal power, an eleventh lens with positive focal power, a twelfth lens with positive focal power, and a thirteenth lens with positive focal power. The first lens to the ninth lens jointly form a system front group, the ninth lens to the thirteenth lens form a system rear group, the system front group is provided with at least two cemented lenses, and the system rear group is provided with at least one cemented lens. The total optical length can be controlled within 130mm, the magnification can achieve at least 2.35 X high magnification, multi-focal-section adaptation is achieved, and a high-image-quality compact zoom lens can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of optical element technology, and in particular to a magnifying lens. Background Technology

[0002] As an external optical accessory, a teleconverter lens can work in conjunction with the built-in camera module of a mobile phone to effectively expand the focal length range of mobile phone photography, achieve higher magnification optical zoom, and thus meet users' needs for high-quality images in scenarios such as shooting at a distance.

[0003] However, current external teleconverters for mobile phones generally only offer magnification of 1.4×–2.0×. They also suffer from problems such as excessive optical length, large size, poor adaptability, and poor image quality, failing to meet the needs of portable telephoto photography. Summary of the Invention

[0004] Based on this, the present invention provides a teleconverter lens with a magnification of at least 2.35X, which can achieve multi-focal length adaptation, while keeping the total length within 130 mm, thus balancing miniaturization and image quality, and significantly improving portability and adaptability.

[0005] This invention provides a teleconverter lens, comprising: arranged sequentially along the optical axis from the object plane to the image plane;

[0006] The lens comprises a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with negative optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with positive optical power, and a thirteenth lens with positive optical power; the teleconverter lens contains 13 lenses with optical power.

[0007] The first lens to the ninth lens together constitute the front group of the system, and the ninth lens to the thirteenth lens constitute the rear group of the system; both the front group and the rear group of the system have positive optical power; the front group of the system includes at least two cemented lens groups, and the rear group of the system includes at least one cemented lens group.

[0008] Optionally, the combined focal length of the system's front group is denoted as... The combined focal length of the rear group of the system is denoted as . ; Satisfying the relation: .

[0009] Optionally, the first lens and the second lens are cemented together to form a first cemented assembly.

[0010] Optionally, the Abbe number of the first lens is ,satisfy: ;

[0011] The refractive index of the second lens is ,satisfy: .

[0012] Optionally, the third lens, the fourth lens, and the fifth lens are cemented together to form a second cemented assembly.

[0013] Optionally, the Abbe number of the third lens is ,satisfy: ;

[0014] The refractive index of the fourth lens is ,satisfy: ;

[0015] The refractive index of the fifth lens is ,satisfy: .

[0016] Optionally, the focal length of the sixth lens is The focal length of the seventh lens is The focal length of the eighth lens is... ;

[0017] ; ; .

[0018] Optionally, the refractive index of the sixth lens is... ,satisfy; ;

[0019] The refractive index of the eighth lens is ,satisfy: ;

[0020] The refractive index of the ninth lens is ,satisfy; .

[0021] Optionally, the tenth lens and the eleventh lens are cemented together to form a third cemented group;

[0022] The refractive index of the tenth lens is ,satisfy; ;

[0023] The Abbe number of the eleventh lens is ,satisfy; .

[0024] Optionally, the twelfth lens and the thirteenth lens constitute a positive power dual-group of the rear group of the system;

[0025] The focal length of the twelfth lens is ,satisfy: ;

[0026] The focal length of the thirteenth lens is ,satisfy: .

[0027] This invention discloses a magnifying lens, in which the optical imaging lens group is arranged sequentially along the optical axis from the object side to the image side as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, and a thirteenth lens. These lenses are, in order: a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, an eighth negative lens with negative optical power, a ninth negative lens with negative optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with positive optical power, and a thirteenth lens with positive optical power. The optical system can be divided into two lens groups: a front lens group and a rear lens group. In this system, the first to ninth lenses together form the front group, and the ninth to thirteenth lenses form the rear group. The front group has at least two cemented lenses, and the rear group has at least one cemented lens. This teleconverter has an optical length that can be controlled within 130mm, a magnification of at least 2.35X, and multi-focal length adaptability. It can achieve a high-quality compact teleconverter, thus solving the technical problem in the prior art that it is difficult to balance high magnification with miniaturization, high image quality, and adaptability. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a magnifying lens provided in Embodiment 1 of this application;

[0029] Figure 2 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 1 of this application.

[0030] Figure 3 MTF curve of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 1 of this application;

[0031] Figure 4 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 1 of this application.

[0032] Figure 5MTF curve of a teleconverter lens with a combined focal length of 94mm provided in Embodiment 1 of this application;

[0033] Figure 6 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 200mm, provided in Embodiment 1 of this application.

[0034] Figure 7 MTF curve of a teleconverter lens with a combined focal length of 200mm provided in Embodiment 1 of this application;

[0035] Figure 8 This is a schematic diagram of the structure of a magnifying lens provided in Embodiment 2 of this application;

[0036] Figure 9 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 2 of this application.

[0037] Figure 10 This is an MTF curve of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 2 of this application.

[0038] Figure 11 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 2 of this application.

[0039] Figure 12 This is an MTF curve of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 2 of this application.

[0040] Figure 13 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 200mm, provided in Embodiment 2 of this application;

[0041] Figure 14 MTF curve of a teleconverter lens with a combined focal length of 200mm provided in Embodiment 2 of this application;

[0042] Figure 15 This is a schematic diagram of the structure of a magnifying lens provided in Embodiment 3 of this application;

[0043] Figure 16 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 3 of this application.

[0044] Figure 17 This is an MTF curve of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 3 of this application.

[0045] Figure 18 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 3 of this application.

[0046] Figure 19This is an MTF curve of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 3 of this application.

[0047] Figure 20 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 200mm, provided in Embodiment 3 of this application;

[0048] Figure 21 The MTF curve of a teleconverter lens with a combined focal length of 200mm is provided in Embodiment 3 of this application.

[0049] Explanation of reference numerals in the attached figures:

[0050] L1, First lens; L2, Second lens; L3, Third lens; L4, Fourth lens; L5, Fifth lens; L6, Sixth lens; L7, Seventh lens; L8, Eighth lens; L9, Ninth lens; L10, Tenth lens; L11, Eleventh lens; L12, Twelfth lens; L13, Thirteenth lens. Detailed Implementation

[0051] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the present application and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present application are shown in the drawings, not the entire structure. Various modifications and variations can be made to the present application without departing from its spirit or scope, which will be apparent to those skilled in the art. Therefore, the present application is intended to cover modifications and variations of the present application that fall within the scope of the technical solutions claimed in the corresponding claims and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.

[0052] Figure 1 This is a schematic diagram of the structure of a magnifying lens provided in Embodiment 1 of this application, with reference to... Figure 1This application provides a teleconverter lens 100, which includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, and a thirteenth lens L13 arranged sequentially along the optical axis from the object side to the image side. The number of lenses having optical power is 13. In order: the first lens L1 with positive optical power, the second lens L2 with negative optical power, the third lens L3 with positive optical power, the fourth lens L4 with negative optical power, the fifth lens L5 with negative optical power, the sixth lens L6 with positive optical power, the seventh lens L7 with positive optical power, the eighth lens L8 with negative optical power, the ninth lens L9 with negative optical power, the tenth lens L10 with negative optical power, the eleventh lens L11 with positive optical power, the twelfth lens L12 with positive optical power, and the thirteenth lens L13 with positive optical power.

[0053] Among them, the first lens L1 to the ninth lens L9 together form the front group G1 of the system, and the ninth lens L9 to the thirteenth lens L13 form the rear group G2 of the system; both the front group G1 and the rear group G2 of the system have positive optical power.

[0054] Optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and its value is the reciprocal of the focal length. It characterizes the ability of a teleconverting lens to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light; the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a lens group formed by multiple lenses.

[0055] Furthermore, the system's front group G1 has at least two cemented lenses, and the system's rear group G2 has at least one cemented lens. The cemented lens group typically consists of a positive lens and a negative lens. For example, a typical combination uses a high-refractive-index, high-dispersion flint glass as the negative lens and a low-refractive-index, low-dispersion crown glass as the positive lens, cemented together. By selecting materials with different refractive indices and dispersion coefficients, chromatic aberration and spherical aberration can be effectively corrected, thereby achieving high image quality. The cemented surface replaces the original two air-glass interfaces, reducing light loss and stray light, while also helping to shorten the overall system length, achieve miniaturization, and enhance the overall mechanical stability of the structure. As a pre-calibrated integrated component, the cemented lens reduces sensitivity to assembly tolerances such as eccentricity and tilt.

[0056] Specifically, the optical system of the teleconverter lens 100 provided in this application embodiment can be divided into two lens groups: front and rear.

[0057] Among them, the first lens L1 to the ninth lens L9 together constitute the front group G1 of the system, and their combined focal length is denoted as . Lenses L9 through L13 form the rear group G2 of the system, and their combined focal length is denoted as... The focal length ratio of the front and rear groups satisfies: The relationship is as follows: Specifically, the front lens group G1 is the front lens group, with positive optical power, mainly responsible for collecting light from the subject and performing initial convergence. The rear lens group G2 is the rear lens group, also with positive optical power, and the focal length ratio of the front and rear groups satisfies: The relationship between the front and rear lens groups facilitates the achievement of the required high magnification and allows for the correction of aberrations generated by the front lens group through the rear lens group. This application, by rationally setting the focal length ratio of the front lens group G1 and the rear lens group G2, ensures that the entire rear lens group G2 can achieve a stable magnification of over 2.35x, meeting the application's dual requirements for image quality and magnification. Furthermore, this optical power allocation method effectively narrows the optical path while achieving high performance, keeping the total optical length of the entire lens system within 130mm, thus achieving a good balance between system performance and compactness.

[0058] Optionally, in the front group G1 of the system, the first lens L1 and the second lens L2 are cemented together to form a first cemented group. The first lens L1 is made of a high Abbe number material, with an Abbe number of [missing information]. ,satisfy: The second lens L2 is made of a high refractive index material, with a refractive index of 100%. ,satisfy: This application uses a first lens L1 and a second lens L2 cemented together to form a first cemented assembly, and then employs a combination of high Abbe number and high refractive index materials to effectively correct axial chromatic aberration and magnification chromatic aberration of the system. Simultaneously, the high refractive index of the second lens L2 is beneficial for correcting spherical aberration and coma.

[0059] Optionally, the third lens L3, the fourth lens L4, and the fifth lens L5 are cemented together to form a second cemented assembly. The third lens L3 is made of a high Abbe number material, with an Abbe number of [missing information]. ,satisfy: The fourth lens, l4, is made of a medium-to-high refractive index material, with a refractive index of [missing value]. ,satisfy: The fifth lens, L5, is made of a high refractive index material, with a refractive index of [missing value]. ,satisfy: .

[0060] This application forms a second cemented assembly by cementing the third lens L3, the fourth lens L4, and the fifth lens L5 together. This three-cemented structure constitutes a powerful apochromatic and aberration balancing unit, capable of correcting second-order spectra over a wider spectral range and synergistically correcting spherical aberration and coma.

[0061] In another embodiment of this application, the fifth lens L5 may be selectively separated from the second adhesive assembly. This separate design introduces a controllable air gap, providing additional degrees of freedom for aberration correction, particularly beneficial for fine-tuning astigmatism and field curvature, and mitigating the potential risks of optical adhesives in extreme environments, thereby achieving an optimal balance between improved performance and guaranteed reliability.

[0062] Furthermore, the combined focal length of the system's front group G1 is denoted as... The focal length of the sixth lens L6 is ,satisfy: The focal length of the seventh lens L7 is... The combined focal length with the system's front group G1 Between, satisfying: The focal length of the eighth lens L8 is... The combined focal length with the system's front group G1 Between, satisfying: The refractive index of the sixth lens L6 is... ,satisfy; The refractive index of the eighth lens l8 is... ,satisfy: .

[0063] Specifically, the sixth lens L6 and the seventh lens L7 employ continuous positive optical power, forming the core converging unit of the system's front group G1. This endows the system with strong light convergence capabilities, effectively compressing the light propagation path behind the system and the required lens aperture, laying the foundation for shortening the overall length. The eighth lens L8 employs negative optical power, effectively correcting the large amount of positive spherical aberration and positive field curvature generated by the first two positive lenses, significantly smoothing the image plane curvature. The high refractive index materials used in both the sixth lens L6 and the eighth lens L8 reduce the lens surface curvature while maintaining the required optical power, thereby effectively suppressing spherical aberration and coma, and reducing higher-order aberrations. This application, through the "positive-positive-negative" optical power structure of the sixth lens L6, the seventh lens L7, and the eighth lens L8, acts as an efficient aberration management and optical path compression unit, collaboratively controlling the overall length and aberration level of the system's front group G1. This allows the teleconverter lens 100 to achieve excellent high-quality performance within a compact size of less than 130mm in overall length.

[0064] Furthermore, the ninth lens L9 has negative optical power, and the refractive index of the ninth lens L9 is... ,satisfy; The ninth lens, L9, employs negative optical power primarily to compensate for the positive Petzwald field curvature generated by the front group G1 of the system, thereby effectively smoothing the image plane. Simultaneously, the high-refractive-index material used allows for a flatter surface when imparting the required negative optical power, significantly reducing higher-order aberrations such as spherical aberration and coma generated by the lens itself. Furthermore, the use of a high-refractive-index material enables the achievement of the required optical power over a shorter physical distance, which also helps to shorten the optical path.

[0065] Furthermore, the tenth lens L10 uses a high refractive index optical material with a refractive index of ,satisfy; Furthermore, the eleventh lens L11 uses a high Abbe number material, with an Abbe number of [missing information]. ,satisfy; .

[0066] The high refractive index of the tenth lens L10 in this application helps suppress residual spherical aberration and astigmatism in the system, while its low Abbe number produces specific chromatic aberration. Meanwhile, the high Abbe number of the eleventh lens L11 accurately corrects chromatic aberration caused by the preceding lenses. Combining the tenth and eleventh lenses L10 with high refractive index and high Abbe number creates an effective chromatic aberration compensation mechanism. This significantly reduces off-axis chromatic aberration in the rear group G2 of the system, improves chromatic aberration correction capability at the edges of the field of view, and thus ensures excellent resolution and image quality for the teleconverter lens 100.

[0067] Furthermore, the twelfth lens L12 and the thirteenth lens L13 form a positive power doublet of the rear group G2 of the system, and the focal length of the twelfth lens L12 is... ,satisfy: The focal length of the thirteenth lens L13 is... ,satisfy: This application, by precisely controlling the focal length ratio of the two sets of positive lenses, allocates a stronger positive optical power to the twelfth lens L12 and the thirteenth lens L13, meaning that the rear group G2 of the system also undertakes a significant converging task. This reduces the optical power of the front group, allowing it to guide the light convergence in a gentler manner, forming a smaller, more controllable beam and shortening the overall system length. Simultaneously, the high refractive index material used in the thirteenth lens L13 significantly reduces the lens surface curvature while maintaining the required positive optical power, and the flat lens surface effectively suppresses higher-order quantities of spherical aberration and coma.

[0068] Optionally, refer to Figure 1In this application, the aperture stop STO is positioned between the thirteenth lens L13 and the image plane M. This arrangement ensures a larger light aperture after light passes through, increasing the aperture number F of the optical system. This ensures clear imaging of objects at different distances simultaneously, as well as clear imaging in low-light environments, thus meeting the usage requirements under various conditions. Furthermore, the first lens L1 to the thirteenth lens L13 and the aperture stop STO can also be housed in a single lens barrel ( Figure 1 (Not shown in the image) This is to achieve the setting of the positions of each lens in the magnifying lens and ensure the stability of the optical path structure.

[0069] In summary, by reasonably setting the refractive index, Abbe number, lens structure, and focal length of the teleconverter lens, the magnification of the teleconverter lens can reach at least 2.35X, and the total system length can be kept within 130mm, ultimately achieving the characteristics of miniaturization, high adaptability, and high image quality.

[0070] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the magnifying lens applicable to the above-described embodiments.

[0071] Example 1

[0072] Continue to refer to Figure 1 The teleconverter lens 100 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, a thirteenth lens L13, and an aperture stop S10, arranged sequentially along the optical axis from the object side to the image side. The number of lenses with optical power is 13. The lenses are arranged in the following order: a first lens L1 with positive optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with negative optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, a twelfth lens L12 with positive optical power, and a thirteenth lens L13 with positive optical power. Lenses L1 through L9 together form the front group G1 of the system, and lenses L9 through L13 form the rear group G2 of the system. Both the front group G1 and the rear group G2 have positive optical power.

[0073] Table 1 details the specific optical physical parameters of each lens in the magnifying lens provided in Embodiment 1 of the present invention.

[0074] Table 1 Design values ​​of optical physical parameters of each lens in the teleconverter lens

[0075]

[0076] The surface number is determined by the order of the lenses' surfaces. For example, surface number "S1" represents the object plane side of the first lens L1, surface number "S2" represents the image plane side of the first lens L1, and so on. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image plane, with the center closer to the image plane, while a negative value indicates that the surface bends towards the object plane, with the center closer to the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite, with the unit being mm. The thickness represents the axial distance from the center of the current surface to the next surface, with the unit being mm. The number of digits varies depending on the parameter's value. This can lead to focusing errors, so the thickness of the STO (Side Target Tolerancing) aperture is not given a specific value; it is "adjusted as needed," and the value can be adjusted as needed to achieve a clear focus. Simultaneously, since this system is a telephoto system, the image is focused at infinity. Therefore, a paraxial surface is set at the STO to test the lens image quality. The paraxial surface can be considered as an ideal thin lens element. Material (nd) represents the refractive index, which is the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air, with a refractive index of 1. Material (vd) represents the Abbe number, which is the dispersion characteristic of the material between the current surface and the next surface. A blank space indicates that the current position is air. Half-diameter represents the lens half-aperture.

[0077] Several performance tests were conducted on the teleconverter lens provided in Example 1, and the specific test results are as follows:

[0078] Figure 2 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 1 of this application. Figure 3 This is an MTF (Modulation Transfer Function) curve of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 1 of this application. Figure 3 MTF (Mean Transform) is one of the most crucial and objective indicators for evaluating the imaging quality of an optical system. It reflects the lens's ability to reproduce contrast at different spatial frequencies (i.e., the level of detail). In this graph, the horizontal axis represents spatial frequency, measured in line pairs per millimeter (lp / mm), and the vertical axis represents the MTF value, ranging from 0 to 1. Figure 3 A graph typically contains multiple curves, each representing the MTF performance under different fields of view. For each field of view, two curves are usually provided, representing the MTF values ​​in the meridional and sagittal directions, respectively. Combined with... Figure 2 and Figure 3The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-100 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0079] Figure 4 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 1 of this application. Figure 5 The MTF curve of a teleconverter lens provided in Embodiment 1 of this application at a combined focal length of 94mm is shown in the figure. Figure 4 and Figure 5 The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-80 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0080] Figure 6 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 200mm, provided in Embodiment 1 of this application. Figure 7 The MTF curve of a teleconverter lens provided in Embodiment 1 of this application at a combined focal length of 200mm is shown in the figure. Figure 6 and Figure 7 The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-60 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0081] Example 2

[0082] Figure 8 This is a schematic diagram of the structure of a magnifying lens provided in Embodiment 2 of this application, with reference to... Figure 8The teleconverter lens 100 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, a thirteenth lens L13, and an aperture stop S10, arranged sequentially along the optical axis from the object side to the image side. The number of lenses with optical power is 13. The lenses are arranged in the following order: a first lens L1 with positive optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with negative optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, a twelfth lens L12 with positive optical power, and a thirteenth lens L13 with positive optical power. Lenses L1 through L9 together form the front group G1 of the system, and lenses L9 through L13 form the rear group G2 of the system. Both the front group G1 and the rear group G2 have positive optical power.

[0083] Table 2 details the specific optical physical parameters of each lens in the magnifying lens provided in Embodiment 2 of the present invention.

[0084] Table 2 Design values ​​of optical physical parameters of each lens in the teleconverter lens

[0085]

[0086] The surface number is determined by the order of the lenses' surfaces. For example, surface number "S1" represents the object plane side of the first lens L1, surface number "S2" represents the image plane side of the first lens L1, and so on. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image plane, with the center closer to the image plane, while a negative value indicates that the surface bends towards the object plane, with the center closer to the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite, with the unit being mm. The thickness represents the axial distance from the center of the current surface to the next surface, with the unit being mm. The number of digits varies depending on the parameter's value. This can lead to focusing errors, so the thickness of the STO (Side Target Tolerancing) aperture is not given a specific value; it is "adjusted as needed," and the value can be adjusted as needed to achieve a clear focus. Simultaneously, since this system is a telephoto system, the image is focused at infinity. Therefore, a paraxial surface is set at the STO to test the lens image quality. The paraxial surface can be considered as an ideal thin lens element. Material (nd) represents the refractive index, which is the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air, with a refractive index of 1. Material (vd) represents the Abbe number, which is the dispersion characteristic of the material between the current surface and the next surface. A blank space indicates that the current position is air. Half-diameter represents the lens half-aperture.

[0087] Several performance tests were conducted on the teleconverter lens provided in Example 2, and the specific test results are as follows:

[0088] Figure 9 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 2 of this application. Figure 10 The MTF curve of a teleconverter lens provided in Embodiment 2 of this application at a combined focal length of 53mm is shown in the reference diagram. Figure 9 and Figure 10 The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-100 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0089] Figure 11 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 2 of this application. Figure 12 The MTF curve of a teleconverter lens provided in Embodiment 2 of this application at a combined focal length of 94mm is shown in the reference diagram. Figure 11 and Figure 12The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-80 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0090] Figure 13 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 200mm, provided in Embodiment 2 of this application. Figure 14 The MTF curve of a teleconverter lens provided in Embodiment 2 of this application at a combined focal length of 200mm is shown in the reference diagram. Figure 13 and Figure 14 The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-60 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0091] Example 3

[0092] Figure 15 This is a schematic diagram of the structure of a magnifying lens provided in Embodiment 3 of this application. (Continue referring to...) Figure 15 The teleconverter lens 100 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, a thirteenth lens L13, and an aperture stop S10, arranged sequentially along the optical axis from the object side to the image side. The number of lenses with optical power is 13. The lenses are arranged in the following order: a first lens L1 with positive optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with negative optical power, a tenth lens L10 with negative optical power, an eleventh lens L11 with positive optical power, a twelfth lens L12 with positive optical power, and a thirteenth lens L13 with positive optical power. Lenses L1 through L9 together form the front group G1 of the system, and lenses L9 through L13 form the rear group G2 of the system. Both the front group G1 and the rear group G2 have positive optical power.

[0093] Table 3 details the specific optical physical parameters of each lens in the magnifying lens provided in Embodiment 3 of the present invention.

[0094] Table 3 Design values ​​of optical physical parameters of each lens in the teleconverter lens

[0095]

[0096] The surface number is determined by the order of the lenses' surfaces. For example, surface number "S1" represents the object plane side of the first lens L1, surface number "S2" represents the image plane side of the first lens L1, and so on. "STO" represents the aperture stop of the lens. The radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image plane, with the center closer to the image plane, while a negative value indicates that the surface bends towards the object plane, with the center closer to the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite, with the unit being mm. The thickness represents the axial distance from the center of the current surface to the next surface, with the unit being mm. The number of digits varies depending on the parameter's value. This can lead to focusing errors, so the thickness of the STO (Side Target Tolerancing) aperture is not given a specific value; it is "adjusted as needed," and the value can be adjusted as needed to achieve a clear focus. Simultaneously, since this system is a telephoto system, the image is focused at infinity. Therefore, a paraxial surface is set at the STO to test the lens image quality. The paraxial surface can be considered as an ideal thin lens element. Material (nd) represents the refractive index, which is the ability of the material between the current surface and the next surface to deflect light. A blank space indicates that the current position is air, with a refractive index of 1. Material (vd) represents the Abbe number, which is the dispersion characteristic of the material between the current surface and the next surface. A blank space indicates that the current position is air. Half-diameter represents the lens half-aperture.

[0097] Several performance tests were conducted on the teleconverter lens provided in Example 3, and the specific test results are as follows:

[0098] Figure 16 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 53mm, provided in Embodiment 3 of this application. Figure 17 The MTF curve of a teleconverter lens provided in Embodiment 3 of this application at a combined focal length of 53mm is shown in the reference diagram. Figure 16 and Figure 17 The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-100 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0099] Figure 18 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 94mm, provided in Embodiment 3 of this application. Figure 19 The MTF curve of a teleconverter lens provided in Embodiment 3 of this application at a combined focal length of 94mm is shown in the reference diagram. Figure 18 and Figure 19The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-80 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0100] Figure 20 This is a schematic diagram of the optical path of a teleconverter lens with a combined focal length of 200mm, provided in Embodiment 3 of this application. Figure 21 The MTF curve of a teleconverter lens provided in Embodiment 3 of this application at a combined focal length of 200mm is shown in the reference diagram. Figure 19 and Figure 20 The MTF characteristic curve of the optical system shows that the 100-fold teleconverter lens exhibits excellent imaging performance in the spatial frequency range of 0-60 cycles / mm, and the meridional and sagittal curves highly coincide, proving that the system effectively controls astigmatism and field curvature, achieving the image quality requirements of high resolution and high contrast.

[0101] In summary, the optical physical parameters of the first lens to the thirteenth lens in Embodiments 1, 2 and 3 of this application are shown in Table 4.

[0102] Table 4 Design values ​​of optical physical parameters for teleconverter lenses

[0103]

[0104] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Features of various embodiments of the present invention can be partially or wholly coupled or combined with each other, and can cooperate and be technically driven in various ways. Various obvious changes, readjustments, combinations, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A teleconverter lens, characterized in that, Including those arranged sequentially along the optical axis from the object plane to the image plane: The lens comprises a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, a ninth lens with negative optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with positive optical power, and a thirteenth lens with positive optical power; the teleconverter lens contains 13 lenses with optical power. The first lens to the ninth lens together constitute the front group of the system, and the ninth lens to the thirteenth lens constitute the rear group of the system; both the front group and the rear group of the system have positive optical power. The front group of the system includes at least two sets of cemented lens groups, and the rear group of the system includes at least one set of cemented lens groups.

2. The teleconverter lens according to claim 1, characterized in that, The combined focal length of the front group of the system is denoted as . The combined focal length of the rear group of the system is denoted as . Satisfying the relation: .

3. The teleconverter lens according to claim 1, characterized in that, The first lens and the second lens are cemented together to form a first cemented assembly.

4. The teleconverter lens according to claim 3, characterized in that, The Abbe number of the first lens is ,satisfy: ; The refractive index of the second lens is ,satisfy: .

5. The teleconverter lens according to claim 1, characterized in that, The third lens, the fourth lens, and the fifth lens are cemented together to form a second cemented group.

6. The teleconverter lens according to claim 5, characterized in that, The Abbe number of the third lens is ,satisfy: ; The refractive index of the fourth lens is ,satisfy: ; The refractive index of the fifth lens is ,satisfy: .

7. The teleconverter lens according to claim 1, characterized in that, The focal length of the sixth lens is The focal length of the seventh lens is The focal length of the eighth lens is... The combined focal length of the system's front group G1 is denoted as... Satisfying the relation: ； ； 。 8. The teleconverter lens according to claim 7, characterized in that, The refractive index of the sixth lens is ,satisfy; ; The refractive index of the eighth lens is ,satisfy: ; The refractive index of the ninth lens is ,satisfy; .

9. The teleconverter lens according to claim 1, characterized in that, The tenth lens and the eleventh lens are cemented together to form a third cemented group; The refractive index of the tenth lens is ,satisfy; ; The Abbe number of the eleventh lens is ,satisfy; .

10. The teleconverter lens according to claim 1, characterized in that, The twelfth lens and the thirteenth lens constitute a positive optical power dual-group in the rear group of the system; The focal length of the twelfth lens is ,satisfy: ; The focal length of the thirteenth lens is ,satisfy: .

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